The spell or ability that caused you to vote will finish resolving before Grudge Keeper’s ability is put on the stack. The ability will be put on the stack even if the results of the vote cause Grudge Keeper to leave the battlefield.

5/29/2014

If one of your opponents has additional votes because of Brago’s Representative, and that player votes for more than one choice you didn’t vote for, that player will lose only 2 life.

5/29/2014

If you have additional votes because of Brago’s Representative, and you vote for more than one choice, an opponent will lose 2 life only if they voted for none of those choices.

5/29/2014

Grudge Keeper’s ability considers only the vote that caused it to trigger, not any previous votes, even if they were caused by the same permanent.